1. Field of the Invention
The present invention relates to a digital Audio/Video (A/V) system, and more particularly to a digital A/V system and method which can support digital systems including digital TV (DTV), digital VCR (DVCR), and digital versatile disk (DVD) player.
2. Background of the Invention
An A/V system is generally an integration of appliances such as TV, VCR and audio system for the purpose of storing and reproducing a variety of media. Currently, the A/V system primarily supports analog forms of video and audio. Accordingly, the A/V system interchanges an NTSC video signal and a digital-to-analog converted audio signal in the appropriate input/output format to support the operation of appliances.
However, with the rapid development of digital multimedia, the image resolution and the number of music channels increased significantly without affecting the functions of the TV, VCR and audio system. Thus, watching an image and listening to voice or music have been greatly enhanced by the development of the digital multimedia. Consequently, the methods for providing and implementing the images and audio for viewing and listening have also changed.
FIG. 1 is a block diagram of a High Definition TV (HDTV) receiver system in the related art; FIG. 2 is a block diagram of a DVCR system in the related art; and FIG. 3 is a block diagram of a DVD player system in the related art. Generally, in every system shown in the figures, the A/V signals are converted from analog to digital signals before processing in the respective systems and compression/expansion techniques are utilized for efficient storage and transmission of substantial amount of digital data. The HDTV receiver, DVCR and DVD player systems will next be described.
Referring to the HDTV in FIG. 1, a TV signal selected by a tuner 11 is forwarded to a Vestigial Sideband (VSB) demodulator 12. Because the TV signal is VSB modulated before transmission, the VSB demodulator 12 demodulates the TV signal to provide a transport stream of a program desired by a user. The transport stream obtained at the VSB demodulator 12 is separated into an audio stream and a video stream through a Transport TS demux (transport demultiplexer) 13, and decoded through an audio decoder 16 and a HD-video decoder 14 respectively. Upon completion of the decoding, the video stream is displayed on an HD monitor 17 through a Video Display Processor (VDP) 15 and the audio stream is played through a speaker 18.
Referring to the DVCR in FIG. 2, a VSB modulated signal is received through a tuner 21, is converted into a transport stream through a VSB demodulator 22 and is forwarded to a Transport TS demux 23. The obtained transport streams is recorded on a tape through a tape recording/reproducing unit 29 through the Transport TS demux 23. However, if a user wants to display the received signals while recording, the signals obtained at the Transport TS demux 23 are separated into a video and audio streams as in the HDTV, and output to a HD-video decoder 24 and an audio decoder 26 for display on a HD monitor 27 through a VDP 25 and speaker 28. To reproduce the signal recorded on the tape, the transport stream is read out from the tape at the tape recording/reproducing unit, separated at the Transport TS demux 23 into the audio and video streams, and output to the respective decoders 24 and 26, thereby facilitating the reproduction of the tape.
Referring to FIG. 3, a DVD disc is read using a DVD ROM 31, and a program stream read from the DVD ROM 31 is separated into a video stream, an audio stream and a sub picture at a Transport Program Stream (Transport PS) demux 32. The video stream and the sub picture are decoded by a SD-video decoder 33, and displayed on an SD monitor 36 through a VDP 34. Also, the audio stream is decoded through an audio decoder 35 and played through a speaker 37.
Unlike an analog system, the digital A/V system utilizes digital forms of input/output data streams defined by set standards. Namely, the input data form for the DTV and DVCR is the transport streams while the input data form for the DVD player is the program stream, as defined by the Motion Picture Expert Group (MPEG) standards (ISO/IEC 13818-1). The data streams are appropriately error correction coded and modulated for transmission and storage according to the transmission paths and storage media. Thus, the streams can be obtained by demodulating and error correction decoding at the respective system. Moreover, each stream contains the compressed video and audio streams as well as additional information such as a timing information for matching A/V synchronization.
Although an analog system utilizes an NTSC composite video signal and two channels of digitized audio signals as input/output signals, the approach to an implementation of the digital A/V system would necessarily differ from the analog system because the digital system utilizes input/output streams defined by standards set by MPEG. FIG. 4 shows an A/V system in the related art which integrates the aforementioned digital systems of FIGS. 1-3, for facilitating the interchange of the aforementioned data streams. The integration shown in FIG. 4 is a simple combination of the digital systems with only a monitor and a speaker in common, using a set interface standard (IEEE 1394). The IEEE 1394 standard is for an effective connection of various domestic appliances, which also allows an interface of general digital A/V.
The IEEE 1394 standard works well for connecting various appliances. However, the combination according to the standard is complicated for interfacing digital A/V appliances, requiring many hardware. Moreover, the cost for implementing even the simple combination of FIG. 4 for interfacing the digital A/V appliances is substantially high.